Glyphland

Thursday, March 15, 2007

First in this year's occasional digressions into NBA blogging. Complaints about topic choice will be considered and then dismissed.

When the Bulls decided to spend every last bit of their cap space on an older version of Tyson Chandler, the Pistons were declared dead. And at first blush, the departure of Ben Wallace has hurt the Pistons severely. The Pistons are on pace for 11 fewer wins this year than they had last year. Opponents average 92.2 points per game, up from 90.2 -- a major leap when the Pistons' overall point differential is just +4.1. But how much of the fall is due to the loss of Wallace? And was resigning him worth it?

We must first establish the players receiving Wallace's minutes. (All numbers from 82games: 05-06, 06-07)

Player

05-06

06-07

Delta

Billups

74

67

-7

Hamilton

71

75

4

Prince

73

77

4

R. Wallace

70

62

-8

McDyess

44

42

-2

Delfino

18

33

15

Maxiell

4

22

18

Davis

4

13

9

Hunter

9

18

9

Arroyo

15

0

-15

B. Wallace

73

0

-73

Evans

29

0

-29

Webber

0

27

27

Mohammed

0

25

25

Murray

0

31

31

Other

7

8

1

Lindsay Hunter and part of Flip Murray have picked up Arroyo's minutes. Delfino and the rest of Murray pick up Evans' minutes. Four post guys receive more time: Webber, Mohammed, Maxiell, and Davis. For convenience's sake we'll apply Davis's minutes to the deficit in Rasheed and McDyess' minutes; Wallace's replacement is the three-headed Webbmomax. Webbmomax plays 74% of the Pistons minutes; Wallace played 73% a year ago.

So what do the Webbmomax Pistons do worse than the Wallace Pistons?

Rebounding? No. Despite losing a man widely regarded as the league's premiere rebounder, Detroit still gathers 69% of its opponents' misses and 30% of its own misses.

Blocks? No. Last year Detroit blocked 7.6% of its opponent's shots. This year it's 7.5%.

Causing turnovers? Last year opponents turned it over on 15% of possessions; this year 16%.

Maybe Wallace had some sort of weird anti-shooting mojo that didn't show up in the blocks? No. Detroit's FG% and eFG% defense percentages are actually better this year (44.3%, 47.6%) than they were last year (45.2%, 47.8%). It should be noted that approximately 1% of opponent's field goals have migrated from jumpers to post moves and dunks, though strangely enough opponents are doing worse at them.

The only thing that jumps out as any different is opposition free throw attempts. This year opponents get 25.3 per game; last year they got only 20.5. That huge discrepancy, plus that extra possession per game, is the only reason the Pistons' D is any worse this year than it was a year ago.

The next question: is that because of Wallace's departure? Survey says yes. Last year Wallace played 73% of the time and picked up 164 fouls, only two per game. The three headed monster that replaces Ben's production is on pace to finish this year with 354 fouls between them. 96% of the excess fouls this year's Pistons are piling up are from Webbmomax.

How many points is this worth per game? If you accept the standard 0.44 multiplier when converting FTAs to FGAs -- and-ones, techs, and the like make it a bit lower than the 0.5 you might expect -- this year Detroit is converting 2.1 FGAs per game into free throws. The free throws are worth 3.55 points; the hypothetical FGAs they replace would be worth 2.01. Wallace's marginal contribution appears to be 1.54 points per game, though it does appear that the more aggressive post defense has created a few more missed shots and a few more turnovers.

Perhaps the revelation that losing Ben Wallace is a detriment to the Piston defense is not Nobel-prize worthy, but what is interesting is where the dropoff is. Rebounding: useless. Blocks: useless (with the stipulation that this is the 05-06 Wallace we're talking about. Previous editions averaged over 3 blocks per game). Contribution to FG defense and opponent turnovers? Negligible or negative. Ben Wallace's main marketable skill is the ability to keep opposing shooters off the foul line.

Let’s go back to Rodman. A key question that, as far as I can tell, is not answered by the WOW authors is this: what is the difference between the number of rebounds the Bulls would have secured with a replacement for Rodman compared to the number they did secure with Rodman? The answer, I am sure is “fewer.” But, how many fewer? If a Rodman replacement snared seven rebounds a game, instead of 15, can we really say that the switch cost the team eight rebounds a game. I don’t think so, and neither, I suspect, do the authors. ...

I agree that rebounds contribute to winning, but to know how much Rodman contributed to winning, we need to know more than how many rebounds he got and we need to know more than how many rebounds he got relative to players on other teams.. What we really need to know is how many rebounds his own team got that it would not otherwise have gotten if he weren’t there. Do I have a clue how to figure that out? Absolutely not. But, I am convinced that that is the key question and that it has not been answered by WOW (and, in fairness, other similar systems).

So how many rebounds did Ben Wallace get that a mediocre version of himself, an undersized version of himself, and a crippled 33 year old power forward could not? This analysis implies, shockingly, that the answer is "none at all." And yet WOW treats each rebound like it's a diamond. As Dan Rosenbaum points out, the whole thing would be wildly off if not for an enormous team defense fudge factor.)

So... is Ben Wallace worth it?

Absolutely not. His yearly numbers are in steady decline and he's in the first year of a four year contract as a 32 year old. And his offensive deficiencies are severe enough that his net contribution is minimal. Webbmomax has hit 178 of 289 free throws this year; Ben Wallace and his 0.407 FT% would have hit 55 fewer and the Pistons would be scoring 0.9 fewer points a game. That's most of his measurable defensive contribution without even considering the rest of his limited offensive game.

At this point in his career, Wallace is an average-at-best starting center who is paid like Kevin Garnett.

So why are the Pistons losing so much more than they did a year ago?

Injuries to Billups and Rasheed. The Billups injury especially, as it ushered in the horrifying Flip Murray Era. The plus-minus numbers for the Pistons' two backup guards are atrocious. It's Billups who's irreplaceable, and it's Billups who Dumars will break the bank for this offseason. If I could put in a request for an MLE point guard, perhaps in exchange for Nazr Mohammed?

Average luck. I don't have any numbers on this, but when you go 64-18 you're a lucky team. I'd be willing to wager that the Pistons' record in close and OT games is markedly worse than it was a year ago.

Familiarity. There was disconnect between the Pistons' regular-season performance and their playoff struggles, but the return to earth started before that. Excluding the four year-end games after the Pistons secured the best record in the league, the team started 37-5 and finished 26-10. Then came the playoffs... ugly. What happened? No one can really be sure, but my belief is the Pistons blitzkrieg caught the league off guard. When Flip Saunders replaced cranky old Larry Brown the Pistons underwent and instant transformation from a pack of ugly grinders into a gorgeous, efficient offensive basketball team. By the time anyone knew what was happening, Chauncey Billups was at Moscow's doorstep. Now that teams have the Pistons scouted, the going is tougher.